Do physician assistants (PAs) and NPs produce the same outcomes of care as physicians in primary care?
The answer to this depends on who is asked; PAs and NPs in the United States tend to differ from allopathic educators on answering this question. One physician association maintains that the minimum of 6 years of didactic and 27.5 weeks of supervised clinical experience should be the standard for training a physician.1 But what about outcomes? Outcomes in this case include quality of care as well as cost of care. Do patients care as long as their needs are met at the same community standards of care and their costs are not increased? The American Association of Medical Colleges believes that PAs and NPs do not substitute for family medicine but provide complementary care at the margins.2 The consensus is that randomized controlled trials are the standard for assessing medication, devices, treatments, and outcomes of care.3
Observational studies to determine if costs of delivering quality primary care are different between physicians, PAs, and NPs must control for other factors such as patient, panel, and organizational structure that could explain differences. To date, four randomized controlled trials have been undertaken with NPs, and all found that they can substitute for primary care physicians in US medicine.4-7 For PAs, no randomized controlled trial has been published but the next best analysis comes from a large observational study looking at outcomes of care that accounted for a wide assortment of variables.8 That work was undertaken by a group of health services researchers at Duke University and the results, released in 2019, are profound because they showed that outcomes of care involving medically complex patients are the same whether the medical provider was a PA, NP, or physician.8 The work builds on mounting evidence that no meaningful quality differences exist between PAs, NPs, and physicians when care is provided in the Veterans Health Administration (VHA).9,10 The study specifically addressed a longstanding concern that if PAs and NPs provide quality care, it is due to increased use of services and will result in increased costs. To address this challenge, the researchers used electronic health record data for a cohort of patients from the VHA who had diabetes. They asked the question: Are costs different when patients are treated by a PA, NP, or physician? To get to this question, the researchers selected the most medically complicated of patients with diabetes and did so by using a unique measure of patient complexity. Patients were identified by important variables such as age, sex, chronic disease score, social complexity measures, access to services, and primary care facility characteristics. The costs to deliver care to this patient cohort by physicians, PAs, and NPs were compared. Costs included inpatient and outpatient episodes, pharmacy, and total healthcare expenses. From this VHA-wide database, only patients who had a long-term relationship with their healthcare provider were selected. Key outcomes were related to endocrinology use and hospitalization expenditures. Drawing on an eligibility pool of 368,481 enrolled veterans, 47,236 (12.8%) met the criteria—still a sizeable group for measuring differences. All of the outcome estimates measured the effect based on the provider type. The combined patient cohort spanned 566 facilities (VHA medical centers and outpatient clinics). An average patient in this analysis was 3.5 times more medically complex than an average Medicare patient. More importantly, no meaningful differences existed between cohorts; patients who were followed by PAs had 6.8 chronic conditions, those with NPs had 6.7, and those with physicians had 6.9. Typically for VA patients, 97% were male, and the mean age was 65 years. All patients saw their 2018 primary care provider at a similar rate of visits. Other variables held constant included post-traumatic stress disorder (17.8% to 18.3%) and homeless in 2012 (3.6% to 4.4%). These were challenging patients to manage both medically and socially.
Yet the results revealed that when patient, panel, and organizational characteristics were accounted for, patients of physicians incurred greater outpatient, pharmacy, and total expenditures compared with those who saw PAs and NPs. Physicians also had higher inpatient costs than PAs and NPs although the outcomes were the same for all three provider arms of the study.8 The big differences were in the inpatient costs and the smaller differences were in outpatient expenditures. As a result, the cumulative effect led to a reduction in total healthcare costs per patient when PAs and NPs were the provider of care than with physicians. This health resource aggregated data translated to a difference of $2,300 less annual cost for patients of PAs than physicians, and $2,005 for NPs than physicians. When this outcome difference is amplified by the hundreds of PAs and NPs in the VHA, the savings are substantial. Had the cost of labor (wages and benefits) been included in the calculations, the dissimilarities would have been larger.
What Morgan and colleagues have done is expand our collective consciousness about the trident of US medical providers—a unique mix of healthcare professionals matched by most countries. By using the prismatic lens of economics, what they revealed is that PAs and NPs can manage complex patients not only effectively but efficiently in a cost-beneficial manner and validate observations that PAs and NPs can safely and adequately substitute for primary care physicians depending on the situation.9-13 These findings are notable for a number of reasons: The federal government has taken advantage of policies laid down over half a century of expanding medicine to a broader range of healthcare professionals.14 The use of PAs and NPs has been a noble experiment that has improved healthcare delivery without compromising safety.15 Nor does patient satisfaction differ between PAs and MDs.16 Furthermore, as the body of knowledge accumulates across countries employing PAs and NPs, the notion of prolonged medical education needs reexamining, as has been called for lately.1,17
1. Dewan MJ, Norcini JJ. Pathways to independent primary care clinical practice: how tall is the shortest giant. Acad Med
2. Association of American Medical Colleges. 2019 Update: The Complexities of Physician Supply and Demand: Projections from 2017 to 2032
. Washington, DC; 2019.
3. Mokkink LB, Terwee CB, Patrick DL, et al. The COSMIN checklist for assessing the methodological quality of studies on measurement properties of health status measurement instruments: an international Delphi study. Qual Life Res
4. Dierick-van Daele ATM, Metsemakers JFM, Derckx EWCC, et al. Nurse practitioners substituting for general practitioners: randomized controlled trial. J Adv Nurs
5. Lenz ER, Mundinger MO, Kane RL, et al. Primary care outcomes in patients treated by nurse practitioners or physicians: two-year follow-up. Med Care Res Rev
6. Mundinger MO, Kane RL, Lenz ER, et al. Primary care outcomes in patients treated by nurse practitioners or physicians: a randomized trial. JAMA
7. Sackett DL, Spitzer WO, Gent M, Roberts RS. The Burlington randomized trial of the nurse practitioner: health outcomes of patients. Ann Intern Med
8. Morgan PA, Smith VA, Berkowitz TSZ, et al. Impact of physicians, nurse practitioners, and physician assistants on utilization and costs for complex patients. Health Aff (Millwood)
9. Virani SS, Akeroyd JM, Ramsey DJ, et al. Comparative effectiveness of outpatient cardiovascular disease and diabetes care delivery between advanced practice providers and physician providers in primary care: implications for care under the Affordable Care Act. Am Heart J
10. Jackson GL, Smith VA, Edelman D, et al. Intermediate diabetes outcomes in patients managed by physicians, nurse practitioners, or physician assistants: a cohort study. Ann Intern Med
11. Timmermans MJC, van den Brink GT, van Vught AJAH, et al. The involvement of physician assistants in inpatient care in hospitals in the Netherlands: a cost-effectiveness analysis. BMJ Open
12. Laurant M, van der Biezen M, Wijers N, et al. Nurses as substitutes for doctors in primary care. Cochrane Database Syst Rev
13. Yang Y, Long Q, Jackson SL, et al. Nurse practitioners, physician assistants, and physicians are comparable in managing the first five years of diabetes. Am J Med
14. Hooker RS. Are physician assistants in America's best interest. JAAPA
15. Brock DM, Nicholson JG, Hooker RS. Physician assistant and nurse practitioner malpractice trends. Med Care Res Rev
16. Hooker RS, Moloney-Johns AJ, McFarland MM. Patient satisfaction with physician assistant/associate care: an international scoping review. Hum Resour Health
17. Cawley JF, Hooker RS. Determinants of the physician assistant/associate concept in global health systems. Int J Healthc